Early life adverse environmental, nutrition and infection factors are associated with lower developmental scores in Pakistani children at 5 years: a cohort study.

Background: The effects of multiple early adverse psychosocial and biological factors on child development at preschool age in deprived settings are not fully understood.

Methods: The 'Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development' (MAL-ED) project followed children from eight countries, recording sociodemographic, nutritional, illness, enteroinfection biomarkers and scores for quality of home environment (Home Observation for Measurement of the Environment (HOME)), development (Bayley) and maternal depression during the first year of life. In the Pakistan cohort, we investigated associations of these early factors with Z-scores (derived from the eight participating countries) of three developmental outcomes at 5 years: Executive Functions (Z-EF), the Wechsler Preschool and Primary Scale for Intelligence (Z-WPPSI) and the externalising behaviours component of the Strength and Difficulties test (Z-externalising behaviours).

Results: Most children had 5-year development measurements below other MAL-ED countries (Z-EF<0, 80.3%, Z-WPPSI<0, 69.3%) and 45.6% had Z-externalising behaviours>0. Higher Z-EF was associated with higher HOME (coeff: 0.03 (95% CI 0.005, 0.05), p=0.017) and Bayley scores (0.01 (0.002, 0.01), p=0.010). Higher Z-WPPSI was associated with more household assets (0.02 (0.01, 0.03), p=0.003), but with lower alpha-1 antitrypsin (µmol/L, protein-losing enteropathy) (-0.01 (-0.02, -0.005), p=0.003). Lower externalising behaviour was associated with female sex (-0.30 (-0.53, -0.08), p=0.009), higher soluble-transferrin-receptors (mg/L) (-0.07 (-0.14, -0.01), p=0.024) and initiation of solids/semisolids≥6 months (-0.16 (-0.31, -0.01), p=0.033), but higher externalising behaviour was associated with underweight (0.35 (0.07, 0.62), p=0.014), more diarrhoeal episodes (0.03 (0.004, 0.06), p=0.022) and higher Maternal Depression Score (0.04 (0.01, 0.07), p=0.003) in the first year.

Conclusion: Adverse environmental, nutrition and infectious factors, and indicators of deprived early development in the first year of life have a negative association with developmental scores at 5 years. Addressing early stressors, improving diet, infections and environment stimulation early in life could positively impact child development in resource-constrained settings.